Accuracy: ?2″.
To inspect protractor, taper gage, index plate, index head and goniometer, can also be used to set angle.
Made of special alloy steel, hardness HRC64, high stability, wear resistance and easy combination.
Can be combined to any angle with interval 6 seconds after combination (6″, 12″, 18″, … , 360?).

3M 85492, Scotch Foil Tape 3311-10A, 2.0 in x 10 yd (50.8 mm x 9,1 m), 7010383663
3M 14502 Scotch-Brite Surface Conditioning Belt, 3/8 in x 13 in, A MED, 7100103026
3M 26016, PPS Series 2.0 Adapter, Type S9, 16 mm Male, 1.5 mm Thread, 7100135330
3M 28476, Disc pad Hub, 2-1/2 in 5/8-11 Internal Low Profile, 7000045288
3M 07394 Hookit Disc Pad, 178 mm x 25 mm M14-2.0 Internal, 7000045702
3M 14215, Roloc Disc Pad TS and TSM, Medium 3 in 1/4-20 Internal, 7000119310
Standard Abrasive 78548, Ceramic Pro Type 29 High Density Flap Disc, 645183, 4 1/2 in x 7/8 40 Y-weight, 7010292440
3M 05035, Cloth Belt 384F, 60+ XF-weight, 1/4 in x 24 in, Fabri-lok, 7100141440, 200 per case
3M 81283, Scotch-Weld High Strength Retaining Compound RT38, Green, 50 mL Bottle, 7010310185, 10/case
3M 76783, Cubitron II Hookit Cloth Disc 784F, 120+ XF-weight, 5 in x NH, Die 500X, 7100222757 
